'consider the Congressional Budget Office estimates of actual median household income. Measured in 2013 dollars, after-tax median income rose briskly from $46,998 in 1983 to $70,393 in 2008 but remained below that 2008 peak in 2011. The sizable increase before 2008 is partly because the average of all federal taxes paid by the middle fifth has almost been cut in half since 1981—from 19.2% that year to 17.7% in 1989, 16.5% in 2000, 13.6% in 2003 and 11.2% in 2011.
Census Bureau estimates of median "money income," on the other hand, do not account for taxes, so they miss a major source of improved living standards. They also exclude realized capital gains, public and private health insurance, food stamps and other in-kind benefits. Even so, the Census Bureau's flawed estimate of median income rose 13.7% from 1984 to 2007 before falling 8% from 2007 to 2013.
Both CBO and Census estimates show only six years of middle-class stagnation…
In their original 2003 study, Messrs. Piketty and Saez mentioned one rapidly expanding source of missing income—disappearing dividends in tax-return data. These were "due mostly to the growth of funded pension plans and retirement savings accounts through which individuals receive dividends that are never reported as dividends on income tax returns."
The same is true of interest and capital gains accumulating inside such tax-free savings accounts. These have grown to nearly $20 trillion, according to a 2014 report by Tax Foundation economist Alan Cole.
Messrs. Piketty and Saez shrink the total income numbers further by subtracting all transfer payments, such as Social Security and unemployment benefits, and excluding all health and retirement benefits provided by private employers or government agencies. The result, as Brookings Institution's Gary Burtless noted, is that, "The Piketty-Saez measure [of total income] excluded 24% of NIPA [National Income and Product Accounts] 'personal income' in 1970, but it excluded 37% of 'personal income' in 2008." It excluded 40% of personal income by 2011. '